KR101195435B1 - Inverse emulsion polymer and method of use thereof - Google Patents

Abstract

The present invention provides an inverse emulsion polymer comprising a dispersed phase consisting of an aqueous solution of an acrylic polymer and a continuous phase consisting of an ester of a fatty acid and a water soluble alcohol. The invention also includes adding the inverse emulsion polymer to an industrial water system; And

It includes a water treatment method comprising the step of hydrolyzing the ester of the fatty acid and the water-soluble alcohol to a fatty acid salt. The inverse emulsion polymer can be used as a flocculant to purify industrial water systems of increased temperature and / or increased pressure and high pH.

Emulsions, inverse emulsions, fatty acids, water soluble alcohols, esters, hydrocarbon-based, flocculants

Description

Inverse emulsion polymer and method of use

The present invention applies a demulsified polymer comprising a discontinuous phase composed of an aqueous solution of an acrylic polymer and a continuous phase composed of an ester of a fatty acid and a water-soluble alcohol, and in particular the demulsified polymer is applied to an industrial water system, and the continuous phase is used as a fatty acid salt. It relates to a water treatment method comprising hydrolysis.

Inverse emulsion polymers have conventionally been used as polymeric flocculants for the separation of fine particulate matter suspended in liquids or slurries obtained during mineral extraction. Inverse emulsion polymers are typically water-in-oil type emulsions that are produced by polymerization techniques to form finely divided aqueous solutions of water-soluble polymers dispersed in oil. Polymeric flocculants separate the suspended particles by incorporating fine particles to form larger aggregates. The increased size of the aggregates causes the aggregates to settle at a significant rate, thereby purifying the liquid. Purification of the liquid in this way is carried out by a settling process, which is typically carried out in large vessels (eg settling tanks or septic tanks) designed for this purpose.

Conventional hydrocarbon-based or paraffin-based flocculants tend to have a detrimental effect on the liquid as well as on systems, facilities or processes downstream of the separation process. The hydrocarbon-based oil phase floats the liquid with increased amounts of organic matter requiring subsequent treatment of the liquid. Moreover, the use of hydrocarbon-based polymeric flocculants in liquids and / or water systems at increased temperatures and / or increased pressures is a substantial risk of explosion of the volatility on the hydrocarbon oil under these conditions and the mineral treatment. It is limited because it involves contamination of the water concentrate obtained during the process.

There is therefore a need for inverse emulsified polymers that do not adversely affect the quality or recovery of subsequent products from the aqueous or liquid to which the emulsion polymer is applied. There is also a need for safe and effective inverse emulsion polymers for application to water-based or liquids at increased temperatures and / or increased pressures.

In one embodiment of the invention, the discontinuous phase consisting of an aqueous solution of an acrylic polymer and an ester of a fatty acid and a water soluble alcohol, a surfactant, a low hydrophilic lipophlic balance emulsifier and a high hydrophilic lip equilibrium emulsifier An inverse emulsion polymer comprising a continuous phase consisting of is provided. The acrylic polymer is selected from the group consisting of salts of (meth) acrylic acid, (meth) acrylate esters, (meth) acrylamide, N-hydroxy (meth) acrylamide and (meth) acrylamidosalicylic acid and salts thereof. It can be synthesized with one or more monomers. Examples of esters of fatty acids and water-soluble alcohols include fatty acid methyl ester oils, soybean oil, methylated soybean oil, ethylated soybean oil, methyl soyate, ethyl soyate, methyl palmitate, methylstearate, methyloleate , Methyl linoleate, methyl linolinate, laurate-based oils, castor oil, linseed oil, coconut oil, corn oil, cottonseed oil, neatfoot oil, olive oil, palm oil, peanut oil, rapeseed oil oils, safflower oil, sesame oil, sperm oil, sunflower oil, tall oil, tallow and mixtures thereof, but are not limited thereto.

In another embodiment, the present inverse emulsion polymer is used to aggregate suspended particles present in mineral extraction systems at elevated temperatures and / or increased pressures and high pH. As used herein, “high pH” means at least about 8 and typically in the range of 12-14. In this embodiment, the ester of the fatty acid and the water soluble alcohol is readily hydrolyzed to the fatty acid salt to produce a nonvolatile byproduct that does not impart substantially vapor pressure on the system. In addition, the fatty acid salts can be separated from the aggregated granulated agglomerates to obtain a clarified liquid with little or no organic matter deposited therein. This advantageously contributes to the recovery of subsequent mineral precipitates with a higher level of purity compared to mineral precipitates obtained from liquids purified with conventional hydrocarbon-based flocculants.

In another embodiment of the present invention, a method for preparing an inverse emulsion polymer is provided. The method is one selected from the group consisting of salts of (meth) acrylic acid, (meth) acrylate esters, (meth) acrylamide, N-hydroxy (meth) acrylamide and (meth) acrylamidosalicylic acid and salts thereof Or adding an aqueous solution of more monomers to an oil phase comprising an ester of a fatty acid and a water soluble alcohol, an emulsifier of a high hydrophilic equilibrium ratio, an emulsifier of a low hydrophilic equilibrium ratio and a surfactant; And initiating polymerization to form the inverse emulsion polymer.

Additional features and advantages of the invention will be apparent from the following detailed description of the preferred embodiments.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention relates generally to inverse emulsion polymers, also referred to as reversible oil-in-water polymer emulsions or latex polymers. The inverse emulsion polymer of the present invention comprises a discontinuous or dispersed aqueous phase consisting of a solution of an acrylic polymer, an ester of a fatty acid and a water-soluble alcohol, an emulsifier of a low hydrophilic equilibrium ratio, an emulsifier of a high hydrophilic equilibrium ratio and a surfactant. . The discontinuous phase is dispersed as micron sized particles in a continuous oil phase, as is commonly known in the art.

The inverse emulsion polymers of the present invention initially comprise salts of (meth) acrylic acid, (meth) acrylate esters, (meth) acrylamide, N-hydroxy (meth) acrylamide and (meth) acrylamidosalicylic acid and salts thereof It can be prepared by dissolving one or more monomers selected from the group consisting of to form the appropriate monomer or aqueous solution of monomers.

As used herein, "(meth) acrylic acid" means acrylic acid or methacrylic acid, "(meth) acrylamide" means acrylamide or methacrylamide, and "hydroxy (meth) acrylamide" Means hydroxyacrylamide or hydroxymethacrylamide, "(meth) acrylate ester" means alkyl and aryl esters of (meth) acrylic acid, and "(meth) acrylamidosalicylic acid" means acrylamido Salicylic acid or methacrylic amido salicylic acid. "AMPS" means 2-acrylamido-2-methylpropanesulfonic acid. Representative salts include sodium salts, potassium salts and ammonium salts.

In one embodiment, a chelating agent may be added to the aqueous solution. Subsequently, the low hydrophilic equilibrium emulsifier, the high hydrophilic equilibrium emulsifier, and the crab surfactants can be dissolved in the oil derived from the vegetable. Subsequently, the aqueous solution may be added to the oil phase to form an emulsion.

The polymerization can be initiated by free radical polymerization or redox polymerization as is well known in the art to form the acrylic polymer. In one embodiment, the trademarked Vazo 64 and the trademarked Vazo® 52 are used as free radical initiators. The acrylic polymer may be prepared by polymerizing the appropriate monomer at a temperature of 30 to 85 ° C. for 1 to 24 hours. In one embodiment, the polymerization takes place over 3 to 6 hours at a temperature of 40 to 70 ° C. In addition, a stabilizer may be added to the emulsion to stabilize the polymer. In one embodiment, the stabilizer can be selected from the group consisting of polyisobutylene derivatives having polyalkylene end groups, ammonium thiocyanate and combinations thereof.

The discontinuous phase of the inverse emulsion polymer may be an aqueous solution of an acrylic polymer. In one embodiment, the acrylic polymer comprises salts of (meth) acrylic acid, (meth) acrylate esters, (meth) acrylamide, N-hydroxy (meth) acrylamide and (meth) acrylamidosalicylic acid and Homopolymers or copolymers of one or more monomers selected from the group consisting of salts. In another embodiment, the acrylic polymer is poly (meth) acrylic acid, poly (meth) acrylic acid including hydroxysaconic acid pendant group, poly (meth) acrylic acid including salicylic acid pendant group, polyalkyl (meth) acrylate, ( (Meth) acrylic acid / (meth) acrylamide copolymers comprising a meta) acrylic acid / alkyl (meth) acrylate copolymer, a (meth) acrylic acid / (meth) acrylamide copolymer, and a hydroxamic acid pendant group, and a salicylic acid pendant group (Meth) acrylic acid / (meth) acrylamide copolymer, (meth) acrylic acid / (meth) acrylamide / alkyl (meth) acrylate terpolymer, and (meth) acrylic acid / (meth) acrylamide / AMPS 3 It may be selected from the group consisting of the copolymers. Thus, it will be understood by those skilled in the art that the acrylic polymer may comprise acrylamide, acrylic acid and / or acrylate monomers in any combination, number and form.

The continuous phase comprises esters of fatty acids and water soluble alcohols. Esters of the fatty acids and water soluble alcohols may be of animal or plant origin or synthetic. In one embodiment, the ester of a fatty acid and a water soluble alcohol is a fatty acid ester derived from one or more fatty acids having 12 to 20 carbon atoms and one or more water soluble hydroxyl compounds, wherein the hydroxyl compound is monohydrate It is a siloxane compound (for example monohydric alcohol) or a polyhydric alcohol compound (for example glycerol). Preferred water-soluble alcohols are hydroxyl compounds having 1 to 4 carbon atoms. It is to be understood that the ester of the fatty acid and the water soluble alcohol is a mixture of different alkyl chain lengths and different saturation or unsaturated degrees depending on the raw material.

Suitable fatty acid ester oils include fatty acid methyl esters, soybean oil, methylated soybean oil, ethylated soybean oil, methyl soyate, ethyl soyate, methyl palmitate, methylstearate, methyloleate, methyllinoleate, methyllinolinate, laurate -Base oils, castor oil, linseed oil, coconut oil, corn oil, cottonseed oil, palm oil, olive oil, palm oil, peanut oil, rapeseed oil, safflower oil, sesame oil, diesel oil, sunflower oil, tall oil, resin and Mixtures of these are included, but are not limited to these. In one embodiment, the continuous phase consists entirely of esters of the fatty acids and water soluble alcohols. In another embodiment, the ester of fatty acid and water soluble alcohol is methyl soyate.

In one embodiment, the continuous phase consists entirely of plant derived oils.

In another embodiment, the plant-derived oil is a fatty acid methyl ester, soybean oil, methylated soybean oil, ethylated soybean oil, methyl soyate, ethyl soyate, methyl palmitate, methylstearate, methyloleate, methyllinoleate, methyl Linoleate, laurate-based oils and mixtures thereof.

In another embodiment, the ester of fatty acid and water soluble alcohol is selected from methyl esters and ethyl esters of fatty acids having 16 to 18 carbon atoms.

The low hydrophilic equilibrium ratio emulsifier may be one having a hydrophilic equilibrium ratio of 1.5 to 7.5. In one embodiment, the hydrophilic equilibrium ratio of the low hydrophilic equilibrium ratio emulsifier may be from 2 to 6. Suitable low hydrophilic equilibrium ratio emulsifiers include sorbitan fatty acid esters, ethoxylated sorbitan esters of fatty acids, or mixtures thereof. In one embodiment, the low hydrophilic equilibrium emulsifier can be sorbitan monooleate, polyoxyethylene sorbitan monostearate or mixtures thereof.

The high hydrophilic equilibrium ratio emulsifier may be one having a hydrophilic equilibrium ratio of 9 to 16. Suitable high hydrophilic equilibrium ratio emulsifiers may include polyoxyalkenesolbitan fatty acid esters as is well known in the art. In one embodiment, the high hydrophilic equilibrium emulsifier is polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitanate and mixtures thereof Included.

The surfactant of the inverse emulsion polymer of the present invention may be made of a polyoxyalkylene modified block copolymer as is well known in the art. In one embodiment, the surfactant may be oil soluble / water insoluble and has a polyhydroxyfatty acid hydrophobic group bound to a polyethylene hydrophilic group. In another embodiment, the surfactant may be a polyisobutylene derivative having polyoxyalkylene end groups suitable for stabilizing the polymer in the emulsion.

Reduced specific viscosity (RSV) is an indication of the chain length and average molecular weight of the polymer. As is well known in the art, the RSV is measured at a given polymer concentration and temperature. The RSV value for the acrylic polymer of the present invention is at least about 10 dL / g, preferably at least about 20 dL / g. In one embodiment, the RSV of the acrylic polymer is 23 to 32 dL / g.

In one embodiment of the invention, the water treatment method may comprise applying the inverse emulsion polymer to an industrial water system and recovering or otherwise collecting the concentrate from the industrial water system. The concentrate is typically an aqueous solution. In another embodiment, the collection of the concentrate may occur by adding the inverse emulsified polymer as a flocculant during the settling step in a mineral extraction process such as, for example, the Bayer process.

As is well known in the mineral extraction art, the concentrate can be recycled to the extraction process. Alternatively, the concentrate may be imparted to a second industrial water system. Suitable industrial water systems to which the concentrate can be given may include, but are not limited to, boiler systems, wastewater treatment systems, and mineral extraction systems. In one embodiment, the second industrial water system can be a boiler system. In such a situation, the increased temperature of the concentrate may be used to heat and / or power other systems and / or facilities.

Low boiling hydrocarbons present in the oil phase of conventional hydrocarbon-based inverse emulsion polymers tend to collect in the concentrate as is well known in the art. This has the problem that these hydrocarbons can adversely affect any second industrial water system that accepts the concentrate. The hydrocarbon oil components distilled into the concentrate may be coated on piping or other internal surfaces to cause flow resistance and other problems in the second industrial water system such as, for example, a boiler system.

Another advantage of applying the reverse emulsified polymer according to the invention to a mineral extraction system in which the concentrate is recovered is essentially ensuring the hydrolysis of the plant-derived oil to fatty acids in the initial industrial water to substantially reduce the concentrate. Oils, oil components or fatty acids do not appear. Thus, during the collection of the concentrate, substantially all fatty acids remain in the industrial water system to produce a concentrate free of any oil components and / or fatty acid components. It has been found that the alcohol product of the oil hydrolysis appears or otherwise accumulates in the concentrate. Typically this has little or no effect on the second industrial water system, such as, for example, a boiler system, since the alcohol is readily soluble in the concentrate.

For example, in the Bayer process, finely divided bauxite ore is supplied to a slurry mixer, where a basic slurry is prepared. A solution of caustic soda dissolves the oxides of aluminum. The bauxite ore slurry is diluted and passed through one digester or series of immersers, where a high fraction of total alumina obtainable under high pressure and temperature is caustic-soluble. Emitted from the ore as sodium aluminate. After immersion, the slurry is passed through several flash tanks, where it reduces the temperature and pressure of the immersed slurry.

The aluminate slurry leaving the flash tank (flash operation) is generally referred to as the primary settler feed and typically contains 1-20% by weight of base-insoluble components of bauxite ore solids ( "Red mud"), which consists of the insoluble residues left behind or precipitates during immersion. The fine solids are generally separated from the liquid by first deposition by gravity settling or coagulation aid and then by filtration as necessary. Once separated, alumina trihydrate is precipitated from the aqueous sodium hydroxide solution and collected as product.

Conventional hydrocarbon-based inverse emulsion polymers used as flocculants for separating the red mud from the liquid are disadvantageous for several reasons. Conventional hydrocarbon-based flocculants include a significant amount of oil as a carrier to suspend the liquid from which the alumina is separated with an increased amount of organic matter. These organics in the liquid can inhibit the precipitation of alumina. In addition, residual hydrocarbon-based oils of conventional emulsions are volatilized during the flashing or liquid evaporation process to increase the risk of explosion and contamination of the concentrate.

Similarly, the soaked slurry is typically discharged from the flash tank at increased temperature. The primary settler feed is generally not cooled further before entering the first settler stage. Thus, during the sedimentation process, the liquid may be at an elevated temperature (eg, above ambient temperature) and may be between 80 and 120 ° C. These increased temperatures increase the vapor pressure of conventional hydrocarbon-based emulsions, causing the concentrate to contaminate with the hydrocarbon-based oil.

In another embodiment, the inverse emulsion polymer can be used to agglomerate suspended particles in the settling step of the Bayer process. The flocculating material may be a discontinuous aqueous acrylic polymer solution as mentioned above. The present invention provides several advantages over conventional hydrocarbon-based flocculants used in the alumina extraction industry. As mentioned above, the Bayer slurry is basic (eg pH of 9-14) and is typically at an increased temperature of 80-120 ° C. when the flocculant is applied to purify the liquid. The addition of the reverse emulsified polymer of the present invention to the Bayer slurry under these conditions readily hydrolyzes the ester of the fatty acid and the water soluble alcohol to an alcohol such as, for example, a salt of the fatty acid and methanol and the like. It may be soluble or otherwise dissolved in the liquid. Hydrolysis of the ester yields soluble, non-volatile fatty acid salts that do not impart substantially any vapor pressure. The inverse emulsion polymers of the present invention thereby provide a safe and effective flocculant by reducing stress on the system and substantially eliminate the risk of explosion and contamination of the concentrate.

Another advantage of the present invention is that the fatty acids do not accumulate in the liquid as organics as occurs in conventional hydrocarbon-based flocculants. Rather, the fatty acid salt precipitates out of the mud during flocculation.

In another embodiment, the water treatment method comprises adding the reverse emulsion polymer of the present invention to a high pressure decantation mineral extraction system and agglomerating the suspended particles into the discontinuous phase. It includes.

High pressure decantation (HPD), also referred to as double dipping, is a purification technique that has been used in the alumina extraction industry that has recently attracted interest as an improved method for alumina recovery. HPD overcomes many of the disadvantages of traditional alumina extraction, such as boehmite reversion, quartz attack, and caustic losses. HPD avoids these problems associated with the use of pressurized mud separation which is essentially performed at immersion temperatures.

For HPD, the bauxite is fed to a first immersion to extract most of the alumina trihydrate, leaving behind impurities that may include other alumina containing components. The slurry is then sent to a pressure decanter. Separation of the slurry is carried out essentially at immersion conditions. The reverse emulsion polymer of the present invention may then be added to the slurry in the pressurized supernatant separator to agglomerate the suspended particles. The temperature of the slurry in the pressurized supernatant separator may be 120 to 250 ° C. The pressure of the slurry in the pressurized supernatant separator may be 1 to 30 atm.

The slurry may be fed from the pressurized supernatant separator to another submerger operating at a high temperature, typically from 165 to 200 ° C., for extraction of the residue of the alumina.

In another embodiment, the inverse emulsion polymer may be added to separate the mud obtained from the second immersion.

Embodiments of the present invention are described below as illustrative and not restrictive.

Examples

The composition of the inverse emulsion polymer is shown in Tables 1 and 2 below.

weight%
(Furtherance) Weight (g)
(1000 g)
Monomer phase water 12.124 121.2395 67% ammonium acrylate 58.854 588.5375 Versene (trade name, EDTA) 0.008 0.0790
Oil phase
Soi Gold 1100 (trade name) 25.426 254.2590 Span 85 (trade name) 1.400 14.0000 Twin 81 (trade name) 0.100 1.0000 Hypermer B-210 (trade name) 0.500 5.0000
Initiator
Bajo 64 (trade name) 0.041 0.4100 Bajo 52 (trade name) 0.003 0.0250 Sodium Hypophosphite 0.038 0.3800 water 0.057 0.5700 additive 55% Ammonium Thiocyanate 1.450 14.5000 Sum 100.000 1000.0000

Oil phase composition Combination Percentage of composition O ₂ percentage Methyl palmitate C-16 10.0 11.8 Methylstearate C-18 04.0 10.7 saturation% 14.0 Methyl oleate C-18 = 1 25.0 10.8 Methyllinoleate C-18 = 2 53.0 10.9 Methylinolinate C-18 = 3 08.0 10.9 Unsaturated 86.0 Total mean of O ₂ 11.0

A 39.8% ammonium acrylate latex continuous phase in methyl soyate was prepared by the following method. In a 2000 ml reaction flask equipped with a mechanical stirrer, RTD, nitrogen purge tube, condenser and heating and cooling means, 254.2590 g of Soy Gold 1100, 14.0 g of Span 85, 1 g of Twin 81, 0.5 g of Hypermer B-210 Solution A was made by addition. This mixture was heated to 60 ° C. to disperse all components. In a separate vessel (1000 ml flask), Solution B was made by adding 121.2395 g of water, 588.5375 g of 67.00% ammonium acrylate monomer solution made from ammonia and acrylic acid in advance and 0.0790 g of versen. The pH of this solution was adjusted to 7.2.

The emulsion of the two phases was prepared by slowly adding solution B while stirring solution A. The crude emulsion was then emulsified for 60 seconds by means of a high speed “homogenizer” such as an IKA T25 equipped with a medium type generator. The temperature of this emulsion was adjusted to 42 ° C.

Subsequently, initiator trademark Bazo 64 and registered trademark Bazo 52 were added. A nitrogen purge was initiated, the reaction mixture was adjusted to 42 ° C. for 5 hours, and conversion by density was obtained. At 90-95% conversion, a solution of sodium hypophosphite was added. The reaction was heated to 50 ° C. and maintained at 50 ° C. for 2 hours. The reaction was then cooled and the product was filtered through a 100-mesh screen. The product was a soft emulsion with methyl soyate as continuous phase. The RSV of this product was measured on 0.040% of the polymer in 2 mol of sodium nitrate (NaNO ₃ ). The product has an RSV of 30.67.

It will be understood that various modifications and variations to the preferred embodiments described herein may be apparent to those skilled in the art. Such changes and modifications may be made without departing from the spirit and perspective of the present invention and without loss of the accompanying advantages. Accordingly, such modifications and variations are intended to be protected by the appended claims.

Therefore, the present invention applies an inverse emulsion polymer comprising a discontinuous phase composed of an aqueous solution of an acrylic polymer and a continuous phase composed of an ester of a fatty acid and a water-soluble alcohol, and in particular, the inverse emulsion polymer to an industrial water system. There is an effect of providing a water treatment method comprising hydrolysis with.

Claims (27)

In the reverse emulsion polymer for use in liquid purification, A discontinuous phase consisting of an aqueous solution of an acrylic polymer, wherein the acrylic polymer is composed of monomers selected from the group consisting of (meth) acrylic acid and salts thereof; Continuous phase consisting solely of esters of fatty acids and C ₁ -C ₄ water-soluble alcohols; Oil-soluble / water-soluble surfactants; Low hydrophilic equilibrium ratio (HLB) emulsifiers from 1.5 to 7.5; And A high hydrophilic equilibrium ratio (HLB) of 9 to 16; The inverse emulsion polymer is characterized in that the inverse emulsion polymer has a low specific viscosity (RSV) value of at least ten. delete delete delete delete delete delete delete delete The method of claim 1, Groups of emulsifiers having a high hydrophilic equilibrium ratio of 9 to 16 consist of polyoxyethylene sorbitan laurate, polyoxyethylene sorbitan palmitate, polyoxyethylene sorbitan stearate, polyoxyethylene sorbitanate and mixtures thereof Inverse emulsion polymer, characterized in that selected from. delete delete delete The method of claim 1, Inverse emulsion polymer, characterized in that the inverse emulsion polymer has a low specific viscosity (RSV) value of at least 20. delete delete delete delete delete delete delete delete delete delete delete delete In the process for producing an inverse emulsion polymer for use in liquid purification, An aqueous solution of monomers selected from the group consisting of (meth) acrylic acid and salts thereof is selected from the group consisting of esters of fatty acids and C ₁ -C ₄ water-soluble alcohols, emulsifiers with a high hydrophilic equilibrium ratio of 9-16, low hydrophilic equilibrium of 1.5-7.5 Adding to an oil phase consisting solely of a ratio of emulsifiers and oil soluble / insoluble surfactants; And Initiating polymerization to form an inverse emulsion polymer; Including the Wherein said inverse emulsion polymer has a low specific viscosity (RSV) value of at least ten.